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Invalid CSL Version

xml
The version attribute on <cs:style> is not a recognized CSL version.

Q-9-15 — Invalid CSL Version

The version attribute on <cs:style> is not a recognized CSL version.

What this means

Every CSL style declares the CSL specification version it targets: <cs:style version="1.0" ...>. The version is used to pick the right validation rules and the right rendering semantics. This error fires when the version attribute is present but does not parse as a valid CSL version — usually because it is not in the major.minor format the parser expects.

Why this happens

Common causes:

  • A typo — version="0.1" instead of version="1.0".
  • A missing or extra character that breaks the major.minor shape.
  • A vendor-specific version string added by another tool that the parser does not recognize.

How to fix

Set version to a valid CSL version string in major.minor form — "1.0" for the current CSL 1.0 specification, or "1.1" for the in-progress 1.1 work. Match the version that the rest of the style was authored against.